肝豆状核变性是因为下列哪种物质代谢障碍所引起的（）
A.铁
B.锌
C.镁
D.铜
E.铅
参考答案：D
所有的角都有一个顶点和两条边。[ ]
A car engine cannot run smoothly without motor oil.____ our body cannot function efficiently without vitamins.
A． fortunately
B． Gradually
C． Similarly
D． Confidently
